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Cooperative Extension Service |
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Agricultural
Experiment Station |
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Aquaculture Division Home
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Forage and Pasture
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| Mesh sieve size | % material passing this sieve size |
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|---|---|---|---|---|---|
| 10 | 90 | ||||
| 60 |
40 |
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| 100 | 25 | ||||
| Particle Size Ranges | % of Material Retained by Each Sieve | Efficiency Factor | Effectiveness Rating | ||
| Coarser than 10 mesh | 10 | multiplied by | 0 | = | 0.0 |
| 10 - 60 | 50 | multiplied by | 0.40 | = | 0.20 |
| 60 -100 | 15 | multiplied by | 1.0 | = | 0.15 |
| Finer than 100 mesh | 25 | multiplied by | 1.0 | = | 0.25 |
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Effective Rating of Product |
= | 0.60 | |||
Finely ground limestone is more effective at neutralizing soil acidity than coarsely ground limestone assuming similar CCE content. A simple calculation for comparing quality of liming materials is to calculate the Effective Liming Material (ELM)of each lime product. The ELM takes into account the fineness of grind as well as the Calcium Carbonate Equivalent of the product.
To do this, multiply the CCE of the lime by the Effectiveness Rating that was calculated as shown above. For example, a material having 90% CCE and an Effectiveness Rating of 0.60 would have an ELM percentage of 54% (0.90 x 0.60 x 100 = 54%). On a ton basis this limestone would contain 1080 lbs. of ELM. Another limestone product having a CCE of 85% and an Effectiveness Rating of only 0.50 would have an ELM percentage of 42.5% (0.85 x 0.50 x 100 = 42.5%) and would contain only 850 lbs. of ELM per ton. The material with the higher ELM per ton will neutralize more soil acidity.
Cost-effectiveness is also important when choosing a liming material. One lime product may have a higher ELM, but also may have a higher cost. The product with the lowest cost per pound of ELM material is the best buy since a pound of ELM material will neutralize the same amount of acidity regardless of the source. The best way to determine the best buy when comparing two sources of lime is to calculate the cost per pound of ELM. This can be done by simply dividing the cost per ton in cents by the lbs. of ELM per ton as shown below.
| Sample 1 | Sample 2 | |
|---|---|---|
| Price per ton (spread on the field) | $22.00 | $18.00 |
| ELM per ton | 1080 | 850 |
| Price per lb. ELM | 2.03¢ (2200/1080) | 2.12¢ (1800/850) |
In this example Sample 1 is the best buy. It is cheaper per pound of ELM even though it has a higher cost per ton.
Producers near the Missouri border may have an option to purchase lime from vendors in either Arkansas or Missouri. In Missouri, Effective Neutralizing Material (ENM) values are used to compare quality of limestone sources. The calculation for determining the amount of ENM per ton is similar to the calculation for ELM per ton. ENM is calculated by multiplying the percent ELM as shown previously by 800 which is a constant that refers to the amount of effective calcium in one ton of pure lime.
For example a limestone with an ELM percentage of 54% would have an ELM of 1080 lbs. per ton but would have an ENM value of 432 lbs. per ton (800 x 0.54=432). Another sample of ag lime having an ELM of 45% would have an ENM value of 360. Both ENM and ELM are simply calculated values that can be used to rank limestone products for soil acidity neutralizing value. The limestone product with the highest value for ELM or ENM is the best quality ag lime.
Developed by
Dr. John Jennings, Extension Livestock Specialist - Forages
Mr. Shane Gadberry, Assistant Livestock Specialist
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University of Arkansas • Division of Agriculture |
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